Hepatoma is the most common cancer in males and the third most common cancer in females in Taiwan; it is a malignant tumor that responds poorly to current therapies may be candidate for boron neutron capture therapy (BNCT). BNCT is based a nuclear reaction occurring when boron-10 is irradiated with and absorbs thermal, epitlhermal neutrons. A situation in which an atom of boron-10 captures a neutron, causes an unstable isotope, boron-11, to form. The boron-11 instantly decomposes, yielding lithiumLi-7 nuclei and energetic alpha particles. Alpha particles have a pathilcngtli of about one cell diameter and give rise to closely spaced ionizing radiation. Thus, these heavy particles are a highly lethal form of radiation; a few alpha particles releasing their energy within a cancer cell are necessary to destroy it. Above characteristics make BNCT highly destroying cancer cells.
Several recent developments have markedly enhanced the potential of BNCT. If the treatment proceeds as intended, the capture reaction's destructive effects occur primarily in cancer cells having accumulated boron-10. Normal cells with low boron concentrations are spared. Investigators are exploring potential boron carriers such as drugs, monoclonal antibodies and derivatives of naturally occurring compounds. Lipiodol has important therapeutic potential as a carrier vehicle for targeting anti-cancer drugs or radio-isotopes for cancer treatment. Encouraging results has been reported in some studies [Kanematsu T. Matsumliata T, Furulta T, Shirabe K, Yamagata M, Utsunomiya T, Sugimachi K. Lipiodol drug targeting in the treatment of primary hepatocellular-carcinonma. Hepato-Gastroenterology (1990) 37:442-444; Lui W Y, Liu R S, Chiang J H, Lo J C, Lai K H, King K L, Cheng H C, Wei Y Y, Chi C W, Peng F K, Chan W K. Report of a pilot study of intra-arterial injection of I-131 lipiodol for the treatment of hepatoma. Chin Med J (Taipei) (1991) 46:125-133]. Moreover, the present inventor and her co-workers in their previously study clearly demonstrated that hepatoma cells in culture are capable of rapidly active uptake of a large quantity of lipiodol by endocytosis with prolonged retention of the lipiodol intracellularly as long as the life span of the cells [Chou F I, Fang K C, Chung C, Lui W Y, Chi C W, Liu R S Chan W K. Lipiodol uptake and retention by human hepatoma cells. Nucl Med Biol (1995) 22(3):379-386]. These findings have major clinical implications for developing new treatment methods for hepatoma patients. To reduce the general toxicity in normal cells in BNCT, in this invention, the present inventor employed lipiodol vesicles as a drug carrier capable of achieving boron drug transport of cancer.